You would still have the same age, gender, personality, skin color, etc. and you would be able to speak at least one local language and would know basic information of the era and place. Your family, social standing, and such would be randomly picked.
A steel bycicle will surely work.
The problem with all of it is going to be scale. I think you’re right in that you think you can just jump into the technology bit in these Yankee in King’s Arthur’s Court scenarios and instead you’d probably get stuck trying to revolutionize mining and material science and then die from an ingrown toenail.
Which, to his credit, Twain absolutely covers when he does the thought experiment. I’m constantly impressed that his take was “you’d cherry pick the people that are open minded enough and spend the rest of your life trying to set up an education system only to be chased away regardless because politics is a bitch”.
That’s still probably the right answer.